Justification:
This species is definitely known from the type collection made in 1805 and a further collection in 1910. More recently it was observed in Kalalau in 1987, Honopu in 1991, and the upper Nuʻololo Stream region in 1995. No living individuals of this species are thought to exist at present hence it is assessed as Extinct. Its extinction was probably due to the impacts on alien invasive plants and animals.

Melicope macropus is endemic to the island of Kauaʻi in the state of Hawai'i. Historically it was known from a region of Waimea. Between 1987 and 1995, it was observed in Kalalau, Honopu, and upper Nuʻololo stream. (Wood 2012).

Major threats to this taxon included predation and habitat destruction by introduced animals such as feral goats and pigs and deer, which are all in relatively high numbers in the areas it once occurred. Displacement by non-native, invasive plant taxa were also a major threat. Such invasive plant species included Rubus rosifolius, R. argutus, Hedychium garderianum, and Kalanchoe pinnata (Wood 2012).